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410A

HI THE QUESTION i have is the 410a two diffrent blends and some talk i am hearing is that you can not add new to leaking system. That you are to take all the old out and replace it with new. Because of the twwo blends.

R-410A is termed a near azeotrope and performs as a pure fluid; laboratory and field tests show no composition shift in the refrigerant after repeated leak and recharge operations. Good service practices should treat all 400 Series blends equally, and systems should be charged by withdrawing liquid refrigerant from the cylinder

Yes. Typically you meter refrigerant through a manifold set as a liquid, allowing it to expand into a gas that is not going to slug the compressor and damage its internal parts. Doing this with 410A helps avoid what can be a changing proportion of the two refrigerant ingredients in their vapor state in the charging tank.

Back in '07 we had a long running thread on the many questions surrounding 410A, principal among them being, "why do we need a new set of refrigerants?" It appears to me that this is more of a political question than an HVAC question. You might want to search the site for those conversations in order to put 410A into context.

Using this refrigerant is not difficult when you know how, but there are higher pressures and therefore more personal risk involved in its use. If you are an HVAC professional, get your post count up and apply for pro membership. We can help you understand these things better in the pro section.

If you are not a pro, my advice would be to not engage in any work involving HVAC systems.

As I understand you can top off a system with 410 several times, charging with liquid, but after 4 you need to recover, evacuate and recharge because the blend will be sugnificantly changed since one part of the 410 will leak out at a different rate than the other.

I prefer to try and find the leak and fix it, but if you can't find the leak it's good to know that you can top off.

As I understand you can top off a system with 410 several times, charging with liquid, but after 4 you need to recover, evacuate and recharge because the blend will be sugnificantly changed since one part of the 410 will leak out at a different rate than the other.

I prefer to try and find the leak and fix it, but if you can't find the leak it's good to know that you can top off.

As I understand you can top off a system with 410 several times, charging with liquid, but after 4 you need to recover, evacuate and recharge because the blend will be sugnificantly changed since one part of the 410 will leak out at a different rate than the other.

Haven't heard of a 4 time limit. But, I haven't heard of a lot of things.
Did this come from a class. Or from general tech talk.

I prefer to try and find the leak and fix it, but if you can't find the leak it's good to know that you can top off.

Leak repair. Another often over looked avenue of income, and good service practice.

Basically, if you have lost less than 50 % of the charge it is OK to top off AFTER the leak is repaired. It is true the blend does boil off at different rates. This is why blends are charged by liquid.

Beenthere; This came from several differenct classes I was at, one specificly on 410A, the others were spring/fall training classes. But thinking about it I would think that it would depend on how much was added each tiime as it would affect the blend.

Since R-410A acts very much like a single component refrigerant, any change in composition due to a leak is minimal. The system can be topped off, without removing the entire charge. There is no practical limit to the number of times a unit can be topped-off or the refrigerant recovered from a unit. However, we do recommend that all leaks be repaired before topping a system off. Excessive superheat is an indication of low charge, and the possibility of a leak in the system should be considered.